Millers in every corner of the world have witnessed the growth of fuzzy, blue and black mold growing at least in some part of the plant. Whether it covers the inside of mill walls or various parts of equipment, mold is always unwelcome.
Mold growth depends on the structure of a facility and the amount of humidity and dust in the atmosphere, explained Thaddeus B. (Ted) Bownik, who recently retired as manager of an ADM flour mill in North Kansas City, Missouri, U.S.
Anywhere there is a difference in temperature between the outside and inside of an object, condensation occurs and presents a breeding ground for mold.
In the ADM facility where Bownik worked, mold mainly grew on the walls in the tempering and conveying area of the cleaning house. But mold growth is not limited to walls.
"Bulk flour cars and trucks are always suspect to condensation and immediately subject to mold growth," Bownik added.
One flour miller in the U.S. Pacific-Northwest region battles mold growth mainly in spouting and in sifter boxes, and is looking for new ways to tackle mold growth in the tempering water.
"Any mold is bad mold," the miller added.
Charles Dawson, quality assurance manager for a ConAgra mill in Macon, Georgia, U.S., battles mold on wall surfaces and on the outside of the bulk flour storage bins.
"Mold control is a moderate problem — it is not the most important, but it is not a non-issue," Dawson said. "Plenty of mills are very concerned about mold, and they are driven by the concerns of their customers. Large retailers keep a very close eye on such microbiological growth — some inspect [facilities] for it every day."
Weather plays a huge role in mold growth, so each region’s climate can cause mold growth in very different places. "This is a worldwide problem," Bownik said.
Dawson also notes that a mill’s air filtration and air intake system also plays a part in mold occurrence.
WHY FIGHT IT? At the heart of each mill’s battle against mold is the desire for basic sanitation in order to maintain flour quality.
"We are trying to keep the mold counts in the flour down," Dawson said. "By eradicating as much mold as you can, it lessens the occurrence of mold in the flour. Where there’s mold, there tends to be yeast. And where there’s yeast, there tends to be bacteria. It becomes a larger microbiological issue."
Controlling mold is a prerequisite, Bownik said. "It’s an area that you cannot tolerate," he said. "The evidence of mold in a facility would not meet standards of any inspecting agency. The risk of mold growth in a facility is the development of rope-spore growth within the flour itself."
Any mold accumulation could affect the bake of the flour, Bownik added.
The American Institute of Baking, Manhattan, Kansas, U.S., regularly performs food safety inspections at flour mills in the U.S. and internationally. Bill Pursley, vice-president of food safety at AIB, said mold typically grows where there is water or condensation.
"The tempering system is a natural problem," Pursley said. Many other spots in a mill, such as spouts, conveyor legs, bulk trailers and flour storage bins, also can be problem areas, he noted.
AIB tries to help mills find a solution to mold. Pursley suggests insulating a wall, improving air movement and frequent cleaning. "Reducing condensation is the goal," he said.
The AIB also suggests sanitizers, such as quatinary ammonia, an approved sanitizer that is friendly to metal, unlike chlorine. Vinegar has also been used, Pursley noted.
Chlorine also is a much-used substance in the fight against mold. Chlorine tablets are often used in the tempering water to control mold growth, and chlorine solutions have been used to clean walls and the outside of equipment.
Results of cleaning with chlorine vary, lasting anywhere from a couple of weeks to a little over a month.
A NEW OPTION. A new product developed to help fight mold and mildew was presented at the 2000 Association of Operative Millers’ conference and trade show.
Bio-Cat is a general cleaner for mold and mildew made completely of enzymes. The product is non-bacterial,and is designed to clean away mold and to prevent its growth, according to Glenn Bondurant, developer of Bio-Cat and director of research and development at IMIX International, Atlanta, Georgia, U.S.
Bob Amelung, president of St. Louis Factory Supply, Inc., the distributor of Bio-Cat to the milling industry, has demonstrated the product’s safety by squirting the properly diluted Bio-Cat cleaner into his mouth and swallowing.
The manufacturer said that Bio-Cat is generally regarded as safe for direct food contact by the U.S. Department of Agriculture, and is "100% biodegradable and harmless to humans and animals." Bondurant said the product can be applied on "walls and floors, food preparation equipment, food processing equipment, [and] food packaging equipment."
Bondurant said enzymes work for mold and mildew control because they clean a surface thoroughly, penetrating the defensive "biofilm" that bacteria develop as a resistance to sanitizers, such as chlorine.
"Bio-Cat is a natural blend of specific enzymes to catalyze the good bacteria, fungi and molds," Bondurant said. "These ‘good’ enzymes reproduce and starve out the ‘bad’ mold, fungi and bacteria."
When a surface is dry, the "good" bacteria lie dormant, Amelung said. When moisture, dust and "bad" bacteria become present again, these enzymes begin to again reproduce and overcome the mold-causing bacteria, he added.
SEEING GOOD RESULTS. Bownik began preliminary testing of Bio-Cat at his ADM mill in 1998. The cleaner worked especially well on concrete or brick walls without insulation, he said.
"After powerwashing the wall and applying the [Bio-Cat] product, two years later it showed no mold growth," Bownik noted. "It was quite amazing."
Dawson’s ConAgra facility has been using the Bio-Cat cleaner for over a year. Previously, the maintenance department at the mill practiced dry cleaning, scraping the mold off the walls every couple of weeks.
"There’s not a lot of products out there that we were able to use," Dawson said, noting that results with Bio-Cat have lasted about 60 days between sprayings.
Jim White, purchasing agent for a Robin Hood Multifoods mill in Port Colborrne, Ontario, Canada, said his company used chlorine before they began using Bio-Cat to clean the mill walls a year ago.
"The minute employees smell chlorine, they get very nervous," White said. "We are also looking for a similar solution in wheat tempering. We currently add chlorine to wheat tempering water."
The miller in the Pacific-Northwest has been using Bio-Cat for only six months, treating the spouting and sifter boxes where mold often grew in his facility. He admits that he is still in a period of trial and error to find the best application techniques and intervals, but he is still pleased.
"I’m steps ahead by using this than not using it," he said.